In the past, it has been common for wall hangings, such as pictures, mirrors, plate holders, etc., to be hung upon the wall by any one of several "center-balancing" techniques. These techniques differ only by the specific hardware employed and all depend upon the premise that the hanging can be leveled initially by balancing the hanging upon a centrally located nail or other wall-protruding element and resting the lower portion of the wall hanging itself against the wall to hold it in place. This technique has drawbacks or conditions attendant their use that make the "center-balancing" technique undesirable.
One problem is that, whether a nail and wire assembly or a nail and nail-bracket assembly are used, trial and error must be used to locate the wall hanging at the desired height, since the position of the nail on the wall bears no standard relation to final height of the wall hanging. This can result in several unsightly holes in the wall before the proper height is obtained. Another problem is that the conventional methods depend upon gravity to balance and level the wall hanging, so that the nail may also have to be moved to locate the proper horizontal position for the wall hanging. Furthermore, if the hanging is bumped or if the balancing relation is not perfectly centered, the hanging can shift out of position and become unlevel. Another problem is that a relatively large nail must be used for wall hangings of significant weight, since the conventional methods concentrate the full weight of the hanging on the support nail. Finally, the conventional methods result in a hanging which is not parallel to the wall surface, creating an unpleasant appearance.